---

A new article published in the journal Forest Ecology and Management by U.S. Forest Service scientists synthesizes recent findings on the interactions between fire and climate and outlines future research needs. Authored by research meteorologists Yongqiang Liu and Scott Goodrick from the Forest Service Southern Research Station (SRS) and Warren Heilman from the Northern Research Station, the article homes in on the effect of emissions from wildfires on long-term atmospheric conditions.

“While research has historically focused on fire-weather interactions, there is increasing attention paid to fire-climate interactions,” says Liu, lead author and team leader with the SRS Center for Forest Disturbance Science. “Weather, the day-to-day state of the atmosphere in a region, influences individual fires within a fire season. In contrast, when we talk about fire climate, we’re looking at the statistics of weather over a certain period. Fire climate sets atmospheric conditions for fire activity in longer time frames and larger geographic scales.”

Wildfires impact atmospheric conditions through emissions of gases, particles, water, and heat. Some of the article focuses on radiative forcing from fire emissions. Radiative forcing refers to the change in net (down minus up) irradiance (solar plus longwave) at the tropopause, the top of the troposphere where most weather takes place.

Smoke particles can generate radiative forcing mainly through scattering and absorbing solar radiation (direct radiative forcing), and modifying the cloud droplet concentrations and lifetime, and hence the cloud radiative properties (indirect radiative forcing). The change in radiation can cause further changes in global temperatures and precipitation.

“Wildfire emissions can have remarkable impacts on radiative forcing,” says Liu.

“During fire events or burning seasons, smoke particles reduce overall solar radiation absorbed by the atmosphere at local and regional levels. At the global scale, fire emissions of carbon dioxide contribute substantially to the global greenhouse effect.”

Other major findings covered in the synthesis include:

• The radiative forcing of smoke particles can generate significant regional climate effects, leading to lower temperatures at the ground surface.
• Smoke particles mostly suppress cloud formation and precipitation. Fire events could lead to more droughts.
• Black carbon, essentially the fine particles of carbon that color smoke, plays different roles in affecting climate. In the middle and lower atmosphere, its presence could lead to a more stable atmosphere. Black carbon plays a special role in the snow-climate feedback loop, accelerating snow melting.

Land surface changes may be triggered that also play into future effects. “Wildfire is a disturbance of ecosystems,” says Liu. “Besides the atmospheric impacts, wildfires also modify terrestrial ecosystem services such as carbon sequestration, soil fertility, grazing value, biodiversity, and tourism. The effects can in turn trigger land use changes that in turn affect the atmosphere.”

The article concludes by outlining issues that lead to uncertainties in understanding fire-climate interactions and the future research needed to address them.

---

The research, published this month in Nature Communications, was conducted by a team of scientists from Cardiff University’s School of Earth and Ocean Sciences, the Natural History Museum in London and the University of Barcelona.

The scientists studied a marine sediment core off the coast of South Africa and reconstructed terrestrial climate variability over the last 100,000 years.

Dr Martin Ziegler, Cardiff University School of Earth and Ocean Sciences, said: “We found that South Africa experienced rapid climate transitions toward wetter conditions at times when the Northern Hemisphere experienced extremely cold conditions.”

These large Northern Hemisphere cooling events have previously been linked to a change in the Atlantic Ocean circulation that led to a reduced transport of warm water to the high latitudes in the North. In response to this Northern Hemisphere cooling, large parts of the sub-Saharan Africa experienced very dry conditions.

“Our new data however, contrasts with sub-Saharan Africa and demonstrates that the South African climate responded in the opposite direction, with increasing rainfall, that can be associated with a globally occurring southward shift of the tropical monsoon belt.”

Linking climate change with human evolution

Professor Ian Hall, Cardiff University School of Earth and Ocean Sciences, said: “When the timing of these rapidly occurring wet pulses was compared with the archaeological datasets, we found remarkable coincidences.

“The occurrence of several major Middle Stone Age industries fell tightly together with the onset of periods with increased rainfall.”

“Similarly, the disappearance of the industries appears to coincide with the transition to drier climatic conditions.”

Professor Chris Stringer of London’s Natural History Museum commented, “The correspondence between climatic ameliorations and cultural innovations supports the view that population growth fuelled cultural changes, through increased human interactions.”

The South African archaeological record is so important because it shows some of the oldest evidence for modern behavior in early humans. This includes the use of symbols, which has been linked to the development of complex language, and personal adornments made of seashells.

“The quality of the southern African data allowed us to make these correlations between climate and behavioural change, but it will require comparable data from other areas before we can say whether this region was uniquely important in the development of modern human culture” added Professor Stringer.

The new study presents the most convincing evidence so far that abrupt climate change was instrumental in this development.

Related Stories

• Chemistry may save some coral from acidity, Science Online, 19 Dec 2012
• Winners and losers in ocean acidification, Science Online, 31 May 2011
• Coral shines light on rainfall records, Science Online, 10 Feb 2011

Use these social-bookmarking links to share Coral reef spread ‘ruled’ by volcanoes.

Climate disasters displace millions of people worldwide

More than 32 million people fled their homes last year because of disasters such as floods, storms and earthquakes – 98% of displacement related to climate change. Asia and west and central Africa bore the brunt. Some 1.3 million people were displaced in rich countries, with the US particularly affected. Floods in India and Nigeria accounted for 41% of displacement, according to the International Displacement Monitoring Centre and Norwegian Refugee Council
• Floods, cyclones … business and governments must wake up to disaster
• Worst natural disasters of 2012 by numbers displaced – in pictures

• guardian.co.uk, Monday 20 May 2013 13.50 BST

• Print this
• Share
• Contact us

Disaster-induced displacement worldwide in 2012 from the International Displacement Monitoring Centre and Norwegian Refugee Council

Photographer: iDMC/NRC

Posted: 05/21/2013 3:19 pm

Climate Change , Hillary Clinton , Environment , Climate Change , Science , Bill McKibben , Carbon Dioxide , Green News , James Hansen , Climate Science , Methane , Green News

Today I introduce you to 1250now.org. Now, no one should be surprised that we’re passing 400 parts per million carbon dioxide. The surprising part is that we’re getting pretty far along without any real agreements to deal with the problem. And, for many people, more surprising still will be this: In our worsening position, as the early effects of warming begin to be felt, and are already becoming critical around the planet’s polar regions, there must be both a long-term strategy and, now, a separate near-term one — and this near-term strategy can have almost nothing to do with carbon dioxide.

For the long-term strategy, 400ppm carbon dioxide is the midpoint between two views of the future — the conventional “450 future,” which was assumed to correspond to a 2 degrees Celsius rise above pre-industrial temperature, hopefully forming a guardrail against ‘dangerous interference’ with the climate, and a “350 future,” corresponding to a rise of about 1.5 degrees Celsius above pre-industrial, first espoused by climate scientist James Hansen, then popularized by Bill McKibben and his 350.org, and since embraced by more and more major figures in science and politics. Recent research and climate events suggest Hansen’s 350 was correct, and the 450 view was mistaken, but right now we aren’t headed toward either, and, given the current fossil fuel bonanza, might even find ourselves surpassing not 450 but 500ppm in a few decades if something isn’t done. This is a monumental struggle, and must be fought tooth, nail, blood, guts, whatever it takes.

It will take cool heads to prevail in a heating world, however, and one quick path to disaster could be that, too caught up in the intensity of this struggle, we ignore the necessity of the near-term strategy as well. So I would like to introduce you to 1250, a new group I’ve been involved in forming. It has recently come online at 1250now.org, and has launched a petition you can sign and circulate. 1250 does not deal with the long-term stabilization of carbon dioxide, and is focused on the need to act quickly on non-carbon dioxide factors to help near-term climate, making it complementary to 350.org’s long-term carbon dioxide focus. 1250 stands for 1250 parts per billion methane, a practical interim methane target, but the group is also concerned with other things such as black carbon emissions, and an Arctic-wide preservation program involving direct environmental restoration projects must also now be part of it. The 350 goal for carbon dioxide will be difficult to achieve this century (unless geoengineering is used), but there is a good chance that 1250ppb methane could be reached, with a global-scale effort, in less than three decades. One important international study has shown that reductions of methane and black carbon together can cut projected warming between now and 2050 in half.

Peter Wadhams, a leading Arctic sea ice scientist who is part of 1250, projects that summer sea ice is likely to drop to near zero coverage within just a few years. Reductions in carbon dioxide emissions, absolutely essential to ensure long-term climate stability, act too slowly to moderate warming over the next few decades. So if we are going to address this Arctic crisis, or the superstorms, droughts, floods, tornadoes and crop failures of next year, of five years from now, of a decade from now, or even of twenty or thirty years from now, our only tools for doing so are 1) reductions of these short-lived factors, and 2) climate engineering. It is hard to swallow, and both counterintuitive and disconcerting to contemplate, that all the hoped-for renewable energy from solar and wind, and all the closures of those dirty coal plants, so vital to the future of society, will make little difference until we are almost gone or have passed, yet a set of rather humdrum-sounding cuts of methane, black carbon, HFCs, and even a non-greenhouse gas like carbon monoxide, could, taken together, have substantial and rapid impacts on warming for the remainder of our lives.

We might only have a few years left to decide if we really want to pursue 1250, however: to give a rough idea of this, while current natural Arctic methane emissions are highly uncertain, if we leave the Arctic to melt, and the summer sea ice indeed plummets in the next few years, leading to chronic methane releases reaching the atmosphere there increasing, let’s say, three or fourfold, then assuming high-end current release estimates, the best we could do through anthropogenic methane cuts from that point on would likely be just to tread water, holding methane steady, barely lowering its abundance at all! Thus the window on making this 1250 approach highly effective might be rapidly closing, and after this, little else will be left to secure near-term climate except geoengineering. Environmental groups opposed to geoengineering should be buzzing about 1250’s prescriptions like bees around honeysuckle.

Just as Hansen started the 350 movement, 1250’s approach comes from him as well — Hansen originally called it his “alternative scenario” for 21st century warming, and it has recently been updated in the work of Drew Shindell and others, embodied with at least the framework of an institution to enact it, initiated by Hillary Clinton. What we really need right now is to reconfigure Hansen’s alternative scenario into far less time — far less, even, than the updated Shindell version. In order to achieve this, we will likely need to restructure the economic fundamentals of what Clinton and others like Robert Watson (former Chair of the IPCC) have started. That won’t happen without much more public awareness and pressure.

I saw Hansen last September, on the very day that the lowest recorded sea ice extent was announced. He told me that he really wanted to get back to talking about his “alternative scenario,” but just needed to feel sure that something would get done about carbon dioxide. Until Hansen gets the chance to start talking about it again, you can in the meantime help him, and the 1250 goal, by signing and circulating this petition.